ABSTRACT Precision agriculture (PA) increasingly relies on advanced sensing technologies to optimize crop yield, quality, and management practices. In this study, we present a stretchable strain sensor specifically designed for monitoring fruit growth ranging from 8 mm to 20 mm in diameter, a critical window for determining the timing for fruit thinning. The sensor employs a silicone elastomer (Ecoflex 00‐30) as both substrate and encapsulant, and a liquid metal (LM) eutectic alloy (Galinstan) as a sensing/conductive channel. Uniform spray coating was used to deposit LM as a sensing channel. The sensor was reshaped into a cylindrical structure, which enabled conformity to the fruit surfaces. The sensor demonstrates stable electromechanical performance with resistance increasing from 2.4 ± 0.5 to 12.2 ± 0.5 Ω under 150% strain (axial). Environmental testing confirmed durability under UV, moisture, and temperature fluctuations. A field validation test was carried out using a manual, self‐built readout system. The sensor exhibits a promising response during the growth period from 8 to 20 mm. Results from the Lab and field indicate the sensor's durability and reliability, making it suitable for long‐term deployment in fields/orchards. The proposed sensor offers growers actionable data to optimize thinning, irrigation, and fertilization practices by providing periodic monitoring of the fruit growth.
Ullah et al. (Tue,) studied this question.